Maintenance of bulldozers cooling system
The cooling system is a very important system for bulldozers. The cooling system of bulldozers includes diesel engine cooling system and hydraulic transmission cooling system. When maintaining the bulldozer, pay attention to:
1. Use of cooling water:
(1) Distilled water, tap water, rainwater or clean river water should be used as the cooling water of the diesel engine. Dirty water or hard water (well water, mineral water and other water with high salt content) should not be used to avoid scaling and corrosion of the cylinder liner. Only under hard water conditions, it must be softened and replenished before it can be used.
(2) When adding water to the water tank, the cooling system may not be fully filled at one time. After the diesel engine is running, it should be checked again. If it is insufficient, it should be added enough. The cooling system water inlet is located on the top of the bulldozer's small top cover.
(3) In the case of continuous operation, the cooling water should be replaced every 300 hours or so. There are five water discharge gates in the cooling system of the bulldozer diesel engine: 1 at the bottom of the water tank; 2 at the lower part of the water-cooled oil cooler of the diesel engine; 3 at the front end of the diesel engine, at the circulating water pump; 4 at the left front of the transfer case, on the diesel engine body; 5 at the The lower end of the water tank outlet pipe.
2. Scale treatment:
Every 600 hours, the diesel engine cooling system should be scaled.
When dealing with scale, it is generally cleaned with an acidic cleaning solution, and then neutralized with an alkaline aqueous solution. Through a chemical reaction, the water-insoluble scale is converted into water-soluble salts, which are removed with water.
The specific work process is as follows:
(1) Remove the thermostat of the cooling system.
(2) Start the diesel engine to make the water temperature rise to 70-85°C. When the floating scale is turned up, immediately turn off the flame and drain the water.
(3) Inject the prepared acid cleaning solution into the water tank, start the diesel engine, run at 600-800r/min for about 40 minutes, turn off the flame and release the cleaning solution. The preparation of the acid cleaning solution: three kinds of acids are added to the clear water in the following proportions: hydrochloric acid: 5~15% hydrofluoric acid: 2~4% glycolic acid: 1~4%. After mixing well, it is ready to use. In addition, as required, an appropriate amount of polyoxyethylene alkyl allyl ether can be added to improve the permeability and dispersibility of scale, and the use temperature of the acid cleaning solution should not exceed 65 °C.
(4) Then inject sodium carbonate aqueous solution with a concentration of 5% to neutralize the acidic cleaning solution remaining in the cooling system. Start the diesel engine, make it run slowly for 4 to 5 minutes, and then turn off the flame to release the sodium carbonate aqueous solution.
(5) Finally, inject clean water, start the diesel engine, make the running speed high and low, rinse the residual solution in the cooling system with clean water, circulate for a while, then turn off the flame and drain the water. According to this process, cycle operation several times until the water released is neutral by litmus paper inspection.
(6) Within 5 to 7 days after cleaning, the cooling water should be replaced every day to prevent residual scale from clogging the water discharge gate.
3. Use of antifreeze:
In severe cold and low temperature conditions, antifreeze can be used.